1. Field of the Invention
The present invention relates to granular material of water-swellable polymers, a method for the manufacture thereof and its use for the absorption of aqueous solutions, especially body liquids, such as blood and/or urine.
2. Description of Related Art
Today, water-swellable polymers are being used in various manners, particularly in the hygienic field for the absorption of body liquids, such as blood and/or urine. The water-swellable polymers must be capable to bind large amounts of liquid (water or body liquids) within a very short period of time. These known water-swellable finely divided polymers, however, tend to "block", i.e. when contacting water or aqueous solutions the outer layer of the bed becomes sticky and thus prevents the liquid from further penetrating into the innermost of the absorbent.
The water-swellable powder-like finely divided polymers are obtained in a more or less wide spectrum of grain sizes, depending on the method of manufacture, said spectrum starting from fine sizes to coarser grains up to coarse-grains. A typical grain spectrum for a water-swellable polymer ground after drying is in the range of from 10 to 800 .mu.m, whereby the size fraction of 150 to 630 .mu.m is used as absorbent for practical purposes. The fine powder obtained having a grain size of about 10 to 150 .mu.m is too fine for the use as absorbent and is therefore to be regarded as waste, and, moreover, is an annoyance.
Therefore it is the object of the present invention to provide such water-swellable, powderlike polymers in a novel appearance not having the disadvantage of blocking, having the capacity of rapidly absorbing large amounts of liquids and which additionally may be produced in an easy and economical way.